diff --git a/backend/internal/protocol/builtin.go b/backend/internal/protocol/builtin.go
index 9ac43bd0b..88c5b773a 100644
--- a/backend/internal/protocol/builtin.go
+++ b/backend/internal/protocol/builtin.go
@@ -340,7 +340,7 @@ func newAPIChannel1Adapter() Adapter {
 	return videoAdapter(info, func(r GenerationRequest) (RequestSpec, error) {
 		media := make([]map[string]string, 0, len(r.Images)+len(r.Videos)+len(r.Audios))
 		for _, image := range r.Images {
-			media = append(media, map[string]string{"type": "reference_image", "url": mediaValue(image)})
+			media = append(media, map[string]string{"type": mediaRole(image, "reference_image"), "url": mediaValue(image)})
 		}
 		for _, video := range r.Videos {
 			media = append(media, map[string]string{"type": "reference_video", "url": mediaValue(video)})
@@ -365,11 +365,26 @@ func xAIVideosAdapter() Adapter {
 	info.Parameters = videoParams()
 	return videoAdapter(info, func(r GenerationRequest) (RequestSpec, error) {
 		body := map[string]any{"model": r.Model, "prompt": r.Prompt, "duration": defaultInt(r.Duration, 6), "aspect_ratio": defaultValue(r.AspectRatio, "16:9"), "resolution": defaultValue(r.Resolution, "720p")}
-		if len(r.Images) == 1 {
-			body["image"] = map[string]any{"url": mediaValue(r.Images[0])}
-		} else if len(r.Images) > 1 {
+		frameImages, referenceImages, unspecifiedImages := splitVideoImages(r.Images)
+		if len(frameImages) > 0 && len(referenceImages) > 0 {
+			return RequestSpec{}, fmt.Errorf("xAI 视频协议不能同时混用首尾帧和角色参考图")
+		}
+		if len(frameImages) > 1 {
+			return RequestSpec{}, fmt.Errorf("xAI 视频协议最多支持 1 张起始图，不支持尾帧输入")
+		}
+		if len(frameImages) == 1 {
+			body["image"] = map[string]any{"url": mediaValue(frameImages[0])}
+		} else if len(referenceImages) > 0 {
+			refs := make([]any, 0, len(referenceImages))
+			for _, image := range referenceImages {
+				refs = append(refs, map[string]any{"url": mediaValue(image)})
+			}
+			body["reference_images"] = refs
+		} else if len(unspecifiedImages) == 1 {
+			body["image"] = map[string]any{"url": mediaValue(unspecifiedImages[0])}
+		} else if len(unspecifiedImages) > 1 {
 			refs := make([]any, 0, len(r.Images))
-			for _, image := range r.Images {
+			for _, image := range unspecifiedImages {
 				refs = append(refs, map[string]any{"url": mediaValue(image)})
 			}
 			body["reference_images"] = refs
@@ -390,7 +405,7 @@ func arkVideosAdapter() Adapter {
 		}
 		content := []any{map[string]any{"type": "text", "text": r.Prompt}}
 		for _, image := range r.Images {
-			content = append(content, map[string]any{"type": "image_url", "image_url": map[string]any{"url": mediaValue(image)}, "role": "reference_image"})
+			content = append(content, map[string]any{"type": "image_url", "image_url": map[string]any{"url": mediaValue(image)}, "role": mediaRole(image, "reference_image")})
 		}
 		for _, video := range r.Videos {
 			content = append(content, map[string]any{"type": "video_url", "video_url": map[string]any{"url": mediaValue(video)}, "role": "reference_video"})
@@ -428,6 +443,9 @@ func geminiVeoAdapter() Adapter {
 	info := metadata("gemini-veo", "Gemini Veo", "Google", CapabilityVideo, "POST /v1beta/models/{model}:predictLongRunning", "GET /v1beta/{operation_name}", "application/json")
 	info.Parameters = videoParams()
 	create := func(r GenerationRequest) (RequestSpec, error) {
+		if hasVideoImageRole(r.Images, "reference_image") {
+			return RequestSpec{}, fmt.Errorf("Gemini Veo 当前不支持角色或风格参考图生视频，请改用支持 reference_to_video 的模型")
+		}
 		instance := map[string]any{"prompt": r.Prompt}
 		if len(r.Images) > 0 {
 			image := r.Images[0]
@@ -450,6 +468,9 @@ func novitaVideosAdapter() Adapter {
 	info := metadata("novita-video", "Novita 视频", "Novita", CapabilityVideo, "POST /v3/video/create", "GET /v3/async/task-result?task_id={id}", "application/json")
 	info.Parameters = videoParams()
 	return videoAdapter(info, func(r GenerationRequest) (RequestSpec, error) {
+		if hasVideoImageRole(r.Images, "reference_image") {
+			return RequestSpec{}, fmt.Errorf("Novita 视频当前不支持角色或风格参考图生视频，请改用支持 reference_to_video 的模型")
+		}
 		body := map[string]any{"model_name": r.Model, "prompt": r.Prompt, "duration": defaultInt(r.Duration, 5), "aspect_ratio": defaultValue(r.AspectRatio, "16:9")}
 		if len(r.Images) > 0 {
 			body["image_url"] = mediaValue(r.Images[0])
@@ -464,7 +485,13 @@ func miniMaxVideosAdapter() Adapter {
 	return videoAdapter(info, func(r GenerationRequest) (RequestSpec, error) {
 		content := []any{map[string]any{"type": "text", "text": r.Prompt}}
 		for _, image := range r.Images {
-			content = append(content, map[string]any{"type": "image_url", "image_url": map[string]any{"url": mediaValue(image)}, "role": "reference_image"})
+			content = append(content, map[string]any{"type": "image_url", "image_url": map[string]any{"url": mediaValue(image)}, "role": mediaRole(image, "reference_image")})
+		}
+		for _, video := range r.Videos {
+			content = append(content, map[string]any{"type": "video_url", "video_url": map[string]any{"url": mediaValue(video)}, "role": "reference_video"})
+		}
+		for _, audio := range r.Audios {
+			content = append(content, map[string]any{"type": "audio_url", "audio_url": map[string]any{"url": mediaValue(audio)}, "role": "reference_audio"})
 		}
 		body := map[string]any{"model": r.Model, "prompt": r.Prompt, "duration": defaultInt(r.Duration, 6), "content": content}
 		mergeExtra(body, r.Extra, "model", "prompt", "duration", "content", "resolution", "aspect_ratio")
@@ -541,6 +568,10 @@ func buildAgnesCreate(r GenerationRequest) (RequestSpec, error) {
 }
 
 func buildAgnesV25Body(r GenerationRequest) (map[string]any, error) {
+	frameImages, referenceImages, _ := splitVideoImages(r.Images)
+	if len(frameImages) > 0 && (len(referenceImages) > 0 || len(r.Videos)+len(r.Audios) > 0) {
+		return nil, fmt.Errorf("Agnes 2.5 不能同时混用首尾帧和角色、视频或音频参考素材")
+	}
 	mode := firstString(r.Extra, "mode")
 	if mode == "" {
 		switch strings.TrimSpace(r.Operation) {
@@ -550,8 +581,10 @@ func buildAgnesV25Body(r GenerationRequest) (map[string]any, error) {
 			mode = "keyframe"
 		default:
 			switch {
-			case len(r.Videos) > 0 || len(r.Audios) > 0:
+			case len(r.Videos) > 0 || len(r.Audios) > 0 || len(referenceImages) > 0:
 				mode = "reference"
+			case len(frameImages) > 0:
+				mode = "keyframe"
 			case len(r.Images) > 2:
 				mode = "reference"
 			case len(r.Images) > 0:
@@ -610,9 +643,17 @@ func buildAgnesV25Body(r GenerationRequest) (map[string]any, error) {
 		if len(r.Images) == 0 || len(r.Images) > 2 || len(r.Videos)+len(r.Audios) > 0 {
 			return nil, fmt.Errorf("Agnes 2.5 keyframe 模式需要 1 到 2 张图片，且不接受音视频参考")
 		}
-		body["first_frame"] = mediaValue(r.Images[0])
-		if len(r.Images) > 1 {
-			body["last_frame"] = mediaValue(r.Images[1])
+		_, referenceImages, _ := splitVideoImages(r.Images)
+		if len(referenceImages) > 0 {
+			return nil, fmt.Errorf("Agnes 2.5 keyframe 模式不能混用角色或风格参考图")
+		}
+		frameImages := orderedFrameImages(r.Images)
+		if len(frameImages) == 0 {
+			return nil, fmt.Errorf("Agnes 2.5 keyframe 模式缺少首帧图片")
+		}
+		body["first_frame"] = mediaValue(frameImages[0])
+		if len(frameImages) > 1 {
+			body["last_frame"] = mediaValue(frameImages[1])
 		}
 	case "reference":
 		if len(r.Images)+len(r.Videos)+len(r.Audios) == 0 {
@@ -681,6 +722,10 @@ func buildAgnesV20Body(r GenerationRequest) (map[string]any, error) {
 	if len(r.Videos)+len(r.Audios) > 0 {
 		return nil, fmt.Errorf("Agnes Video V2.0 不支持参考视频或音频")
 	}
+	_, referenceImages, _ := splitVideoImages(r.Images)
+	if r.Operation == "reference_to_video" || len(referenceImages) > 0 {
+		return nil, fmt.Errorf("Agnes Video V2.0 不支持角色或风格参考图模式，请改用 Agnes Video 2.5")
+	}
 	body := map[string]any{"model": r.Model, "prompt": r.Prompt}
 	mergeExtra(body, r.Extra, "mode", "width", "height", "num_frames", "frame_rate", "num_inference_steps", "seed", "negative_prompt")
 	if r.Duration > 0 {
@@ -703,16 +748,17 @@ func buildAgnesV20Body(r GenerationRequest) (map[string]any, error) {
 			body["num_frames"] = frames
 		}
 	}
-	if len(r.Images) == 1 {
-		body["image"] = mediaValue(r.Images[0])
-	} else if len(r.Images) > 1 {
+	orderedImages := orderedFrameImages(r.Images)
+	if len(orderedImages) == 1 {
+		body["image"] = mediaValue(orderedImages[0])
+	} else if len(orderedImages) > 1 {
 		extraBody := map[string]any{}
 		if configured := object(r.Extra["extra_body"]); configured != nil {
 			for key, value := range configured {
 				extraBody[key] = value
 			}
 		}
-		extraBody["image"] = mediaValues(r.Images)
+		extraBody["image"] = mediaValues(orderedImages)
 		extraBody["mode"] = "keyframes"
 		body["extra_body"] = extraBody
 	} else if configured := object(r.Extra["extra_body"]); configured != nil {
@@ -1120,6 +1166,47 @@ func compactMap(body map[string]any) map[string]any {
 	return result
 }
 func mediaValue(media MediaReference) string { return defaultValue(media.URL, media.DataURL) }
+func mediaRole(media MediaReference, fallback string) string {
+	return defaultValue(strings.TrimSpace(media.Role), fallback)
+}
+
+func splitVideoImages(images []MediaReference) (frames []MediaReference, references []MediaReference, unspecified []MediaReference) {
+	firstFrames := make([]MediaReference, 0, 1)
+	lastFrames := make([]MediaReference, 0, 1)
+	for _, image := range images {
+		switch strings.TrimSpace(image.Role) {
+		case "first_frame":
+			firstFrames = append(firstFrames, image)
+		case "last_frame":
+			lastFrames = append(lastFrames, image)
+		case "reference_image":
+			references = append(references, image)
+		default:
+			unspecified = append(unspecified, image)
+		}
+	}
+	frames = append(frames, firstFrames...)
+	frames = append(frames, lastFrames...)
+	return frames, references, unspecified
+}
+
+func orderedFrameImages(images []MediaReference) []MediaReference {
+	frames, _, unspecified := splitVideoImages(images)
+	if len(frames) == 0 {
+		return unspecified
+	}
+	return append(frames, unspecified...)
+}
+
+func hasVideoImageRole(images []MediaReference, role string) bool {
+	for _, image := range images {
+		if strings.TrimSpace(image.Role) == role {
+			return true
+		}
+	}
+	return false
+}
+
 func mediaValues(values []MediaReference) []string {
 	result := make([]string, 0, len(values))
 	for _, value := range values {
diff --git a/backend/internal/protocol/builtin_test.go b/backend/internal/protocol/builtin_test.go
index 9d9e62955..49045fc29 100644
--- a/backend/internal/protocol/builtin_test.go
+++ b/backend/internal/protocol/builtin_test.go
@@ -196,6 +196,62 @@ func TestArkVideoAdapterMapsFullModalReferences(t *testing.T) {
 	}
 }
 
+func TestVideoAdaptersTranslateImageRolesWithoutGuessingFromCount(t *testing.T) {
+	tests := []struct {
+		name string
+		id   string
+		role string
+	}{
+		{name: "newapi channel 1", id: "newapi-channel-1", role: "reference_image"},
+		{name: "volcengine ark", id: "volcengine-ark-video", role: "first_frame"},
+		{name: "minimax", id: "minimax-video", role: "last_frame"},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			adapter, _ := Builtins().Get(test.id)
+			spec, err := adapter.BuildCreate(context.Background(), RequestContext{Request: GenerationRequest{
+				Model: "video-model", Prompt: "test", Duration: 5,
+				Images: []MediaReference{{ID: "image-1", URL: "https://cdn.example/image.png", Role: test.role}},
+			}})
+			if err != nil {
+				t.Fatal(err)
+			}
+			body, _ := json.Marshal(spec.Body)
+			if !strings.Contains(string(body), `"`+test.role+`"`) {
+				t.Fatalf("body does not contain role %q: %s", test.role, body)
+			}
+		})
+	}
+}
+
+func TestXAIVideoUsesReferenceImagesEvenForOneReferenceAsset(t *testing.T) {
+	adapter, _ := Builtins().Get("xai-video")
+	spec, err := adapter.BuildCreate(context.Background(), RequestContext{Request: GenerationRequest{
+		Model: "grok-video", Prompt: "keep the character", Images: []MediaReference{{URL: "https://cdn.example/character.png", Role: "reference_image"}},
+	}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	body := spec.Body.(map[string]any)
+	if body["image"] != nil || body["reference_images"] == nil {
+		t.Fatalf("xAI reference body = %#v", body)
+	}
+}
+
+func TestStartFrameOnlyAdaptersRejectReferenceAssetSemantics(t *testing.T) {
+	for _, id := range []string{"gemini-veo", "novita-video"} {
+		t.Run(id, func(t *testing.T) {
+			adapter, _ := Builtins().Get(id)
+			_, err := adapter.BuildCreate(context.Background(), RequestContext{Request: GenerationRequest{
+				Model: id, Prompt: "keep the character", Images: []MediaReference{{URL: "https://cdn.example/character.png", Role: "reference_image"}},
+			}})
+			if err == nil || !strings.Contains(err.Error(), "reference_to_video") {
+				t.Fatalf("BuildCreate() error = %v", err)
+			}
+		})
+	}
+}
+
 func TestAsyncVideoResponseNormalizesStatusAndResult(t *testing.T) {
 	adapter, _ := Builtins().Get("minimax-video")
 	created, err := adapter.ParseCreate(context.Background(), []byte(`{"task":{"id":"mm-1","status":"processing"}}`))
diff --git a/backend/internal/protocol/types.go b/backend/internal/protocol/types.go
index a8b8a6bc7..e97f7b64c 100644
--- a/backend/internal/protocol/types.go
+++ b/backend/internal/protocol/types.go
@@ -37,9 +37,11 @@ const (
 )
 
 type MediaReference struct {
+	ID        string `json:"id,omitempty"`
 	URL       string `json:"url,omitempty"`
 	DataURL   string `json:"dataUrl,omitempty"`
 	Kind      string `json:"kind,omitempty"`
+	Role      string `json:"role,omitempty"`
 	Ephemeral bool   `json:"ephemeral,omitempty"`
 }
 
diff --git a/backend/internal/service/provider.go b/backend/internal/service/provider.go
index c27d5afa4..eb8fd9ca9 100644
--- a/backend/internal/service/provider.go
+++ b/backend/internal/service/provider.go
@@ -2341,7 +2341,7 @@ func protocolRequestFromInput(input canvasGenerationInput) protocol.GenerationRe
 	request := protocol.GenerationRequest{
 		Model:         input.Config.Model,
 		Prompt:        input.Prompt,
-		Images:        protocolMediaReferences(input.ReferenceImages, "image"),
+		Images:        protocolVideoImageReferences(input),
 		Videos:        protocolMediaReferences(input.ReferenceVideos, "video"),
 		Audios:        protocolMediaReferences(input.ReferenceAudios, "audio"),
 		AspectRatio:   input.Config.Size,
@@ -2370,10 +2370,31 @@ func protocolRequestFromInput(input canvasGenerationInput) protocol.GenerationRe
 	return request
 }
 
+func protocolVideoImageReferences(input canvasGenerationInput) []protocol.MediaReference {
+	result := make([]protocol.MediaReference, 0, len(input.ReferenceImages))
+	fallbackRole := ""
+	if metadataString(input.Metadata, "videoStartFrameNodeId") != "" || metadataString(input.Metadata, "videoEndFrameNodeId") != "" {
+		fallbackRole = "reference_image"
+	}
+	for _, value := range input.ReferenceImages {
+		item := protocol.MediaReference{
+			ID:      strings.TrimSpace(value.ID),
+			URL:     strings.TrimSpace(value.URL),
+			DataURL: strings.TrimSpace(value.DataURL),
+			Kind:    "image",
+			Role:    videoImageRoleOrDefault(input, value, fallbackRole),
+		}
+		if item.URL != "" || item.DataURL != "" {
+			result = append(result, item)
+		}
+	}
+	return result
+}
+
 func protocolMediaReferences(values []providerMedia, kind string) []protocol.MediaReference {
 	result := make([]protocol.MediaReference, 0, len(values))
 	for _, value := range values {
-		item := protocol.MediaReference{URL: strings.TrimSpace(value.URL), DataURL: strings.TrimSpace(value.DataURL), Kind: kind}
+		item := protocol.MediaReference{ID: strings.TrimSpace(value.ID), URL: strings.TrimSpace(value.URL), DataURL: strings.TrimSpace(value.DataURL), Kind: kind}
 		if item.URL != "" || item.DataURL != "" {
 			result = append(result, item)
 		}
@@ -2868,16 +2889,9 @@ func runMiniMaxVideoTask(ctx context.Context, input canvasGenerationInput) (map[
 		if err != nil {
 			return nil, fmt.Errorf("MiniMax 参考图无效：%w", err)
 		}
-		role := "reference_image"
-		if frameMode {
-			switch {
-			case startFrameID != "" && image.ID == startFrameID:
-				role = "first_frame"
-			case endFrameID != "" && image.ID == endFrameID:
-				role = "last_frame"
-			default:
-				return nil, errors.New("MiniMax 首尾帧模式不能混合未标记的参考图")
-			}
+		role := videoImageRole(input, image)
+		if frameMode && role == "reference_image" {
+			return nil, errors.New("MiniMax 首尾帧模式不能混合未标记的参考图")
 		}
 		content = append(content, miniMaxVideoContent{Type: "image_url", ImageURL: &miniMaxMediaURL{URL: url}, Role: role})
 	}
@@ -3014,6 +3028,9 @@ func runGeminiVeoVideoTask(ctx context.Context, input canvasGenerationInput) (ma
 	if len(input.ReferenceImages) > 1 || len(input.ReferenceVideos) > 0 || len(input.ReferenceAudios) > 0 {
 		return nil, errors.New("Gemini Veo 当前只支持 1 张起始图，不支持参考视频或音频")
 	}
+	if len(input.ReferenceImages) > 0 && metadataString(input.Metadata, "videoEditOperation") == "reference_to_video" {
+		return nil, errors.New("Gemini Veo 当前不支持角色或风格参考图生视频，请改用支持 reference_to_video 的模型")
+	}
 	id := resumedProviderRequestID(ctx)
 	if id == "" {
 		instance := geminiVeoInstance{Prompt: strings.TrimSpace(input.Prompt)}
@@ -3074,6 +3091,9 @@ func runNovitaVideoTask(ctx context.Context, input canvasGenerationInput) (map[s
 	if len(input.ReferenceImages) > 1 || len(input.ReferenceVideos) > 0 || len(input.ReferenceAudios) > 0 {
 		return nil, errors.New("Novita 视频当前只支持 1 张起始图，不支持参考视频或参考音频")
 	}
+	if len(input.ReferenceImages) > 0 && metadataString(input.Metadata, "videoEditOperation") == "reference_to_video" {
+		return nil, errors.New("Novita 视频当前不支持角色或风格参考图生视频，请改用支持 reference_to_video 的模型")
+	}
 	id := resumedProviderRequestID(ctx)
 	if id == "" {
 		body := map[string]interface{}{
@@ -3636,7 +3656,7 @@ func newAPIChannel1VideoBody(input canvasGenerationInput) (map[string]interface{
 			if err != nil {
 				return nil, err
 			}
-			media = append(media, map[string]string{"type": seedanceImageRole(input, image), "url": url})
+			media = append(media, map[string]string{"type": videoImageRole(input, image), "url": url})
 		}
 	}
 	for _, video := range input.ReferenceVideos {
@@ -3798,6 +3818,9 @@ func xaiVideoRequestBody(input canvasGenerationInput) (xaiVideoRequest, error) {
 		return body, nil
 	}
 	startFrameID := metadataString(input.Metadata, "videoStartFrameNodeId")
+	if metadataString(input.Metadata, "videoEditOperation") == "reference_to_video" {
+		startFrameID = ""
+	}
 	if startFrameID == "" {
 		// 未设置首帧：所有参考图作为 R2V 参考，不受单张起始图限制。
 		for index := range input.ReferenceImages {
@@ -4874,7 +4897,7 @@ func seedanceContent(input canvasGenerationInput) ([]map[string]interface{}, err
 		if err != nil {
 			return nil, err
 		}
-		content = append(content, map[string]interface{}{"type": "image_url", "image_url": map[string]interface{}{"url": url}, "role": seedanceImageRole(input, image)})
+		content = append(content, map[string]interface{}{"type": "image_url", "image_url": map[string]interface{}{"url": url}, "role": videoImageRole(input, image)})
 	}
 	for _, video := range input.ReferenceVideos {
 		url, err := mediaReferenceURL(video)
@@ -4943,7 +4966,9 @@ func seedanceVideosRequestBody(input canvasGenerationInput) (seedanceVideosReque
 	if err != nil {
 		return seedanceVideosRequest{}, err
 	}
-	if len(frameImageURLs) > 0 {
+	if metadataString(input.Metadata, "videoEditOperation") == "reference_to_video" {
+		body.ReferenceImageURLs = imageURLs
+	} else if len(frameImageURLs) > 0 {
 		body.ImageURLs = frameImageURLs
 	} else if len(imageURLs) > 0 {
 		body.ImageURL = imageURLs[0]
@@ -4993,17 +5018,27 @@ func seedanceVideosPromptText(input canvasGenerationInput) string {
 	return strings.TrimSpace(input.Prompt)
 }
 
-func seedanceImageRole(input canvasGenerationInput, image providerMedia) string {
+func videoImageRole(input canvasGenerationInput, image providerMedia) string {
+	return videoImageRoleOrDefault(input, image, "reference_image")
+}
+
+func videoImageRoleOrDefault(input canvasGenerationInput, image providerMedia, fallback string) string {
+	if metadataString(input.Metadata, "videoEditOperation") == "reference_to_video" {
+		return "reference_image"
+	}
 	if id := metadataString(input.Metadata, "videoStartFrameNodeId"); id != "" && image.ID == id {
 		return "first_frame"
 	}
 	if id := metadataString(input.Metadata, "videoEndFrameNodeId"); id != "" && image.ID == id {
 		return "last_frame"
 	}
-	return "reference_image"
+	return fallback
 }
 
 func videoFrameImageURLs(input canvasGenerationInput, imageURLs []string) ([]string, error) {
+	if metadataString(input.Metadata, "videoEditOperation") == "reference_to_video" {
+		return nil, nil
+	}
 	startFrameID := metadataString(input.Metadata, "videoStartFrameNodeId")
 	endFrameID := metadataString(input.Metadata, "videoEndFrameNodeId")
 	if startFrameID == "" && endFrameID == "" {
diff --git a/backend/internal/service/provider_test.go b/backend/internal/service/provider_test.go
index 39e078b80..d425dcf6c 100644
--- a/backend/internal/service/provider_test.go
+++ b/backend/internal/service/provider_test.go
@@ -1372,6 +1372,31 @@ func TestSeedanceVideosBodyUsesOrderedFrameImageURLsWhenConfigured(t *testing.T)
 	}
 }
 
+func TestSeedanceVideosBodyKeepsProjectAssetsAsReferenceImages(t *testing.T) {
+	body, err := seedanceVideosRequestBody(canvasGenerationInput{
+		Prompt: "keep the character consistent",
+		Config: providerConfig{Model: "seedance-2.0"},
+		ReferenceImages: []providerMedia{
+			{ID: "character-1", DataURL: testReferenceImageDataURL},
+			{ID: "character-2", DataURL: "data:image/png;base64,d29ybGQ="},
+		},
+		Metadata: map[string]interface{}{
+			"videoEditOperation":    "reference_to_video",
+			"videoStartFrameNodeId": "character-1",
+		},
+	})
+	if err != nil {
+		t.Fatalf("seedanceVideosRequestBody() error = %v", err)
+	}
+	want := []string{testReferenceImageDataURL, "data:image/png;base64,d29ybGQ="}
+	if !reflect.DeepEqual(body.ReferenceImageURLs, want) {
+		t.Fatalf("reference_image_urls = %#v, want %#v", body.ReferenceImageURLs, want)
+	}
+	if body.ImageURL != "" || body.ImageURLs != nil {
+		t.Fatalf("reference operation leaked frame fields: %#v", body)
+	}
+}
+
 func TestRunVideoTaskUsesNewAPIForAnyVideoModel(t *testing.T) {
 	t.Setenv("CANVAS_ALLOW_PRIVATE_UPSTREAMS", "true")
 	paths := make([]string, 0, 3)
@@ -1731,6 +1756,22 @@ func TestXAIVideoBodyWithStartFrameKeepsOfficialImageShape(t *testing.T) {
 	}
 }
 
+func TestXAIVideoReferenceOperationIgnoresStaleStartFrameMetadata(t *testing.T) {
+	body, err := xaiVideoRequestBody(canvasGenerationInput{
+		Config: providerConfig{Model: "grok-imagine-video-1.5", InterfaceType: "xai-video"},
+		ReferenceImages: []providerMedia{
+			{ID: "character", DataURL: testReferenceImageDataURL},
+		},
+		Metadata: map[string]interface{}{"videoEditOperation": "reference_to_video", "videoStartFrameNodeId": "character"},
+	})
+	if err != nil {
+		t.Fatalf("xaiVideoRequestBody() error = %v", err)
+	}
+	if body.Image != nil || len(body.ReferenceImages) != 1 {
+		t.Fatalf("xAI reference operation body = %#v", body)
+	}
+}
+
 func TestXAIVideoBodyWithStartFrameRejectsMultipleImages(t *testing.T) {
 	_, err := xaiVideoRequestBody(canvasGenerationInput{
 		Config: providerConfig{Model: "grok-imagine-video-1.5", InterfaceType: "xai-video"},
@@ -1919,6 +1960,38 @@ func TestNewAPIChannel1VideoBodyMapsFramesAndReferences(t *testing.T) {
 	}
 }
 
+func TestProtocolRequestPreservesVideoImageIDsAndRoles(t *testing.T) {
+	request := protocolRequestFromInput(canvasGenerationInput{
+		Mode: "video",
+		ReferenceImages: []providerMedia{
+			{ID: "start", URL: "https://example.com/start.png"},
+			{ID: "character", URL: "https://example.com/character.png"},
+		},
+		Metadata: map[string]interface{}{
+			"videoEditOperation":    "image_to_video",
+			"videoStartFrameNodeId": "start",
+		},
+	})
+	if len(request.Images) != 2 {
+		t.Fatalf("images = %#v", request.Images)
+	}
+	if request.Images[0].ID != "start" || request.Images[0].Role != "first_frame" {
+		t.Fatalf("start image = %#v", request.Images[0])
+	}
+	if request.Images[1].ID != "character" || request.Images[1].Role != "reference_image" {
+		t.Fatalf("unmarked image role = %#v", request.Images[1])
+	}
+
+	request = protocolRequestFromInput(canvasGenerationInput{
+		Mode:            "video",
+		ReferenceImages: []providerMedia{{ID: "character", URL: "https://example.com/character.png"}},
+		Metadata:        map[string]interface{}{"videoEditOperation": "reference_to_video", "videoStartFrameNodeId": "character"},
+	})
+	if request.Images[0].Role != "reference_image" {
+		t.Fatalf("reference operation image = %#v", request.Images[0])
+	}
+}
+
 func TestNewAPIChannel1VideoBodyRejectsInlineMedia(t *testing.T) {
 	_, err := newAPIChannel1VideoBody(canvasGenerationInput{
 		Prompt:          "make it move",
diff --git a/docs/content/docs/progress/pending-test.mdx b/docs/content/docs/progress/pending-test.mdx
index c52c1787b..b50c10579 100644
--- a/docs/content/docs/progress/pending-test.mdx
+++ b/docs/content/docs/progress/pending-test.mdx
@@ -42,6 +42,7 @@ description: 影策已实现功能的手工验证清单与未确认边界
 - [x] 镜头轨道按当前制作阶段显示待生成、生成中、已生成和生成失败状态，状态标签固定在卡片右下角；横向镜头只在轨道内部滚动，不再撑宽脚本区或挤出产物预览。制作概览六个流程节点改为独立可点击卡片；前端类型检查、生产构建与相关专项测试通过。
 - [x] 分镜生成设置接入统一模型选择、能力和计价链路，支持前台模型、系统模型与用户自定义模型；切换模型会归一画幅、分辨率/画质和时长，MiniMax-H3 的旧 `720` 会切换为 `768P`。项目设置可保存默认生图/视频模型；后端全量测试、MiniMax 回归测试和前端生产构建通过。
 - [x] 单镜生成改为任务提交后立即返回，不同镜头可并行进入排队/生成状态；角色卡主图、绑定声音样本和场景资产会按 `图片N` / `音频N` 编译进提示词。MiniMax 项目资产使用 `reference_image` / `reference_audio`，仅显式首尾帧节点使用帧角色；产物固定绑定任务提交时的镜头版本。前后端全量测试与生产构建通过。
+- [x] 视频图片语义统一为首帧、尾帧和普通参考图三类，并贯穿前端直连、后端任务与声明式协议；Agnes、Seedance `/videos`、火山方舟、NewAPI 媒体任务、xAI 和 MiniMax 不再按图片数量误猜项目角色资产。Gemini Veo、Novita 等仅支持起始图的协议会明确拒绝 `reference_to_video`，不再静默降级成首帧。
 - [ ] 在真实项目中初始化一个已有章节，确认不会误用旧 v1 工作流，刷新和切换章节后阶段、镜头和当前版本保持一致。
 - [ ] 在同一章节准备待生成、生成中、已生成和生成失败镜头，确认灰、蓝、绿、红标签始终显示在卡片右下角；增加到几十个镜头后确认只有底部轨道横向滚动，中间脚本和右侧产物预览仍完整可见。
 - [ ] 在浅色、深色、常规桌面和窄屏下检查制作概览六张流程卡片的边界、间距、完成态、悬停和键盘焦点，确认跳转目标正确。
@@ -51,6 +52,7 @@ description: 影策已实现功能的手工验证清单与未确认边界
 - [ ] 在项目设置分别选择系统、用户自定义的默认生图/视频模型，刷新后进入分镜图、动作预演和镜头视频，确认项目默认优先、已下架模型回退全局默认；切换 Seedance、MiniMax-H3 等能力不同的模型时，画幅、时长、分辨率和本次预计积分立即更新，并与实际账单一致。
 - [ ] 连续选择两个镜头并分别提交视频生成，确认两个镜头独立显示“正在提交/生成中”，第二个任务不会被第一个全局锁阻止；刷新页面后两个任务状态都能恢复，完成产物分别绑定各自提交时的镜头版本。
 - [ ] 给镜头绑定带主图和声音样本的角色卡及场景资产，使用 MiniMax-H3 生成并检查请求日志：文本包含 `【资产参考】`、角色声音说明和台词，角色/场景图片为 `reference_image`、声音为 `reference_audio`，请求不再出现误判的 `first_frame`，画幅和 `768P` / `2K` 与界面选择一致。
+- [ ] 使用同一镜头资产依次切换 Agnes 2.5、Seedance `/videos`、火山方舟、NewAPI 媒体任务和 xAI，确认单张角色图仍走 reference 字段；再切换 Gemini Veo、Novita，确认提交前给出“不支持 reference_to_video”的明确提示，而不是把角色图当起始帧生成。
 - [ ] 当前“资产拆分 AI、多宫格生成提交、批量视频任务、后端交付包”仍是后续阶段，界面不得显示为已完成或可用。
 
 ## 角色声音素材绑定
diff --git a/web/src/services/api/video-provider-agnes.ts b/web/src/services/api/video-provider-agnes.ts
index eae4db660..6f0aacfef 100644
--- a/web/src/services/api/video-provider-agnes.ts
+++ b/web/src/services/api/video-provider-agnes.ts
@@ -5,6 +5,7 @@ import type { ReferenceAudio, ReferenceVideo } from "@/types/media";
 
 import type { ApiEnvelope, RequestOptions, ResolvedAiConfig, VideoGenerationTask, VideoGenerationTaskState } from "./video-contracts";
 import type { VideoProviderDeps } from "./video-provider-deps";
+import { resolveVideoImageReferences, type VideoImageRole } from "./video-reference-roles";
 
 type AgnesTaskResponse = {
     id?: string;
@@ -44,9 +45,10 @@ export async function createAgnesVideoTask(
         Promise.all(videoReferences.map((item) => resolveAgnesMediaUrl(item.url, item.storageKey))),
         Promise.all(audioReferences.map((item) => resolveAgnesMediaUrl(item.url, item.storageKey))),
     ]);
+    const imageRoles = resolveVideoImageReferences(references, options, { videoCount: videoUrls.length, audioCount: audioUrls.length }).map(({ role }) => role);
     const payload = modelName === "agnes-video-v2.0"
-        ? buildAgnesV20Payload(config, modelName, normalizedPrompt, imageUrls, videoUrls, audioUrls)
-        : buildAgnesV25Payload(config, modelName, normalizedPrompt, imageUrls, videoUrls, audioUrls);
+        ? buildAgnesV20Payload(config, modelName, normalizedPrompt, imageUrls, imageRoles, videoUrls, audioUrls, options)
+        : buildAgnesV25Payload(config, modelName, normalizedPrompt, imageUrls, imageRoles, videoUrls, audioUrls);
 
     try {
         const raw = await deps.transport.post<ApiEnvelope<AgnesTaskResponse>>(deps.transport.apiUrl("/videos"), payload, options);
@@ -92,7 +94,7 @@ export function agnesPollUrl(config: ResolvedAiConfig, videoId: string, modelNam
     return base.toString();
 }
 
-function buildAgnesV25Payload(config: ResolvedAiConfig, model: string, prompt: string, images: string[], videos: string[], audios: string[]) {
+function buildAgnesV25Payload(config: ResolvedAiConfig, model: string, prompt: string, images: string[], imageRoles: VideoImageRole[], videos: string[], audios: string[]) {
     if (!AGNES_V25_MODELS.has(model)) throw new Error(`Agnes 视频协议不支持模型 ${model}`);
     const seconds = agnesSeconds(config.videoSeconds);
     const size = agnesResolution(config.vquality);
@@ -101,7 +103,10 @@ function buildAgnesV25Payload(config: ResolvedAiConfig, model: string, prompt: s
         if (images.length > 5) throw new Error("Agnes Video 2.5 Flash 最多支持 5 张参考图");
         if (videos.length) throw new Error("Agnes Video 2.5 Flash 不支持参考视频");
     }
-    const mode = videos.length || audios.length || images.length > 2 ? "reference" : images.length ? "keyframe" : "text";
+    const hasReferenceImages = imageRoles.includes("reference_image");
+    const hasFrameImages = imageRoles.includes("first_frame") || imageRoles.includes("last_frame");
+    if (hasFrameImages && (hasReferenceImages || videos.length || audios.length)) throw new Error("Agnes Video 2.5 不能同时混用首尾帧和角色、视频或音频参考素材");
+    const mode = videos.length || audios.length || hasReferenceImages ? "reference" : images.length ? "keyframe" : "text";
     const payload: Record<string, unknown> = {
         model,
         prompt,
@@ -112,8 +117,10 @@ function buildAgnesV25Payload(config: ResolvedAiConfig, model: string, prompt: s
         n: 1,
     };
     if (mode === "keyframe") {
-        payload.first_frame = images[0];
-        if (images[1]) payload.last_frame = images[1];
+        const firstFrame = imageForRole(images, imageRoles, "first_frame") || images[0];
+        const lastFrame = imageForRole(images, imageRoles, "last_frame");
+        payload.first_frame = firstFrame;
+        if (lastFrame) payload.last_frame = lastFrame;
     } else if (mode === "reference") {
         if (images.length) payload.images = images;
         if (audios.length) payload.audios = audios;
@@ -122,8 +129,9 @@ function buildAgnesV25Payload(config: ResolvedAiConfig, model: string, prompt: s
     return payload;
 }
 
-function buildAgnesV20Payload(config: ResolvedAiConfig, model: string, prompt: string, images: string[], videos: string[], audios: string[]) {
+function buildAgnesV20Payload(config: ResolvedAiConfig, model: string, prompt: string, images: string[], imageRoles: VideoImageRole[], videos: string[], audios: string[], options?: RequestOptions) {
     if (videos.length || audios.length) throw new Error("Agnes Video V2.0 不支持参考视频或音频");
+    if (options?.videoEditOperation === "reference_to_video" || imageRoles.includes("reference_image")) throw new Error("Agnes Video V2.0 不支持角色或风格参考图模式，请改用 Agnes Video 2.5");
     const seconds = Math.max(1, Math.floor(Number(config.videoSeconds) || 5));
     const frameRate = 24;
     const targetFrames = seconds * frameRate;
@@ -133,11 +141,17 @@ function buildAgnesV20Payload(config: ResolvedAiConfig, model: string, prompt: s
         frame_rate: frameRate,
         num_frames: Math.min(441, Math.floor((targetFrames - 1 + 4) / 8) * 8 + 1),
     };
-    if (images.length === 1) payload.image = images[0];
-    if (images.length > 1) payload.extra_body = { image: images, mode: "keyframes" };
+    const orderedImages = [imageForRole(images, imageRoles, "first_frame"), imageForRole(images, imageRoles, "last_frame")].filter((value): value is string => Boolean(value));
+    if (orderedImages.length === 1) payload.image = orderedImages[0];
+    if (orderedImages.length > 1) payload.extra_body = { image: orderedImages, mode: "keyframes" };
     return payload;
 }
 
+function imageForRole(images: string[], roles: VideoImageRole[], role: VideoImageRole) {
+    const index = roles.indexOf(role);
+    return index >= 0 ? images[index] : undefined;
+}
+
 function agnesSeconds(value: string) {
     const seconds = Math.floor(Number(value) || 5);
     if (seconds < 4 || seconds > 12) throw new Error("Agnes Video 2.5 时长必须在 4–12 秒之间");
diff --git a/web/src/services/api/video-provider-gemini.ts b/web/src/services/api/video-provider-gemini.ts
index cfe0f5885..854dae35c 100644
--- a/web/src/services/api/video-provider-gemini.ts
+++ b/web/src/services/api/video-provider-gemini.ts
@@ -16,6 +16,7 @@ type GeminiVeoOperation = {
 
 export async function createGeminiVeoTask(deps: VideoProviderDeps, config: ResolvedAiConfig, model: string, prompt: string, references: ReferenceImage[], videoReferences: ReferenceVideo[], audioReferences: ReferenceAudio[], options?: RequestOptions): Promise<VideoGenerationTask> {
     if (references.length > 1 || videoReferences.length || audioReferences.length) throw new Error("Gemini Veo 当前只支持 1 张起始图，不支持参考视频或音频");
+    if (references.length && options?.videoEditOperation === "reference_to_video") throw new Error("Gemini Veo 当前不支持角色或风格参考图生视频，请改用支持 reference_to_video 的模型");
     const instance: Record<string, unknown> = { prompt: prompt.trim() };
     if (references[0]) {
         const dataUrl = await imageToDataUrl(references[0]);
diff --git a/web/src/services/api/video-provider-minimax.ts b/web/src/services/api/video-provider-minimax.ts
index 06f3b25b8..df9785b27 100644
--- a/web/src/services/api/video-provider-minimax.ts
+++ b/web/src/services/api/video-provider-minimax.ts
@@ -9,22 +9,22 @@ import type { ReferenceAudio, ReferenceVideo } from "@/types/media";
 
 import type { MiniMaxVideoCreateResponse, MiniMaxVideoTask, RequestOptions, ResolvedAiConfig, VideoGenerationTask, VideoGenerationTaskState } from "./video-contracts";
 import type { VideoProviderDeps } from "./video-provider-deps";
+import { resolveVideoImageReferences } from "./video-reference-roles";
 
 export async function createMiniMaxVideoTask(deps: VideoProviderDeps, config: ResolvedAiConfig, model: string, prompt: string, references: ReferenceImage[], videoReferences: ReferenceVideo[], audioReferences: ReferenceAudio[], options?: RequestOptions): Promise<VideoGenerationTask> {
     const imageUrls = await Promise.all(references.slice(0, 9).map((image) => resolveMiniMaxImageUrl(image)));
     const videoUrls = await Promise.all(videoReferences.slice(0, 3).map((video) => resolveMiniMaxMediaUrl(video, "参考视频")));
     const audioUrls = await Promise.all(audioReferences.slice(0, 3).map((audio) => resolveMiniMaxMediaUrl(audio, "参考音频")));
     const content: Array<Record<string, unknown>> = [{ type: "text", text: prompt.trim() }];
-    const explicitFrameMode = options?.videoEditOperation !== "reference_to_video" && Boolean(options?.videoStartFrameNodeId || options?.videoEndFrameNodeId);
+    const imagePlan = resolveVideoImageReferences(references.slice(0, 9), options, { videoCount: videoUrls.length, audioCount: audioUrls.length });
+    const frameMode = imagePlan.some(({ role }) => role === "first_frame" || role === "last_frame");
     imageUrls.forEach((url, index) => {
-        const reference = references[index];
-        const role = miniMaxImageRole(reference?.id, options);
-        if (explicitFrameMode && role === "reference_image") throw new Error("MiniMax 首尾帧模式不能混合未标记的参考图");
+        const role = imagePlan[index]?.role || "reference_image";
+        if (frameMode && role === "reference_image") throw new Error("MiniMax 首尾帧模式不能混合未标记的参考图");
         content.push({ type: "image_url", image_url: { url }, role });
     });
     videoUrls.forEach((url) => content.push({ type: "video_url", video_url: { url }, role: "reference_video" }));
     audioUrls.forEach((url) => content.push({ type: "audio_url", audio_url: { url }, role: "reference_audio" }));
-    const frameMode = explicitFrameMode;
     const payload = {
         model: modelOptionName(model),
         content,
@@ -43,13 +43,6 @@ export async function createMiniMaxVideoTask(deps: VideoProviderDeps, config: Re
     }
 }
 
-function miniMaxImageRole(imageId: string | undefined, options?: RequestOptions) {
-    if (options?.videoEditOperation === "reference_to_video") return "reference_image";
-    if (imageId && imageId === options?.videoStartFrameNodeId) return "first_frame";
-    if (imageId && imageId === options?.videoEndFrameNodeId) return "last_frame";
-    return "reference_image";
-}
-
 export async function pollMiniMaxVideoTask(deps: VideoProviderDeps, config: ResolvedAiConfig, task: VideoGenerationTask, options?: RequestOptions): Promise<VideoGenerationTaskState> {
     try {
         const response = await deps.transport.get<{ task?: MiniMaxVideoTask }>(miniMaxVideoUrl(config, `/query/video_generation/${encodeURIComponent(task.id)}`), options);
diff --git a/web/src/services/api/video-provider-novita.ts b/web/src/services/api/video-provider-novita.ts
index 54d91675d..5d7c9972a 100644
--- a/web/src/services/api/video-provider-novita.ts
+++ b/web/src/services/api/video-provider-novita.ts
@@ -12,6 +12,7 @@ type NovitaVideoResult = { task?: { status?: string; reason?: string }; videos?:
 
 export async function createNovitaVideoTask(deps: VideoProviderDeps, config: ResolvedAiConfig, model: string, prompt: string, references: ReferenceImage[], videoReferences: ReferenceVideo[], audioReferences: ReferenceAudio[], options?: RequestOptions): Promise<VideoGenerationTask> {
     if (references.length > 1 || videoReferences.length || audioReferences.length) throw new Error("Novita 视频当前只支持 1 张起始图，不支持参考视频或音频");
+    if (references.length && options?.videoEditOperation === "reference_to_video") throw new Error("Novita 视频当前不支持角色或风格参考图生视频，请改用支持 reference_to_video 的模型");
     const payload: Record<string, unknown> = {
         model: modelOptionName(model),
         prompt: prompt.trim(),
diff --git a/web/src/services/api/video-provider-openai.ts b/web/src/services/api/video-provider-openai.ts
index eb013c1f6..f03f3f4e5 100644
--- a/web/src/services/api/video-provider-openai.ts
+++ b/web/src/services/api/video-provider-openai.ts
@@ -13,13 +13,21 @@ export async function createOpenAIVideoTask(deps: VideoProviderDeps, config: Res
     if (config.interfaceType === "xai-video" || modelName.toLowerCase().includes("grok")) {
         const images = await Promise.all(references.slice(0, 7).map((image) => imageToDataUrl(image)));
         const seconds = normalizeVideoSeconds(config.videoSeconds);
+        const referenceMode = options?.videoEditOperation === "reference_to_video";
+        const explicitFrameMode = !referenceMode && Boolean(options?.videoStartFrameNodeId || options?.videoEndFrameNodeId);
+        if (config.interfaceType === "xai-video" && explicitFrameMode && (images.length > 1 || options?.videoEndFrameNodeId)) throw new Error("xAI 视频协议最多支持 1 张起始图，不支持尾帧或混合角色参考图");
+        const imagePayload = config.interfaceType === "xai-video"
+            ? referenceMode && images.length
+                ? { reference_images: images.map((url) => ({ url })) }
+                : images.length ? { image: { url: images[0] } } : {}
+            : images.length ? { image: images[0], images } : {};
         const payload = {
             model: modelName,
             prompt,
             duration: Number.parseInt(seconds, 10) || 6,
             seconds,
             ...(normalizeVideoSize(config.size) ? { size: normalizeVideoSize(config.size) } : {}),
-            ...(images.length ? { image: images[0], images } : {}),
+            ...imagePayload,
         };
         try {
             const createPath = config.interfaceType === "xai-video" ? "/videos/generations" : "/videos";
diff --git a/web/src/services/api/video-provider-seedance.ts b/web/src/services/api/video-provider-seedance.ts
index a82e69d09..12e84b9e0 100644
--- a/web/src/services/api/video-provider-seedance.ts
+++ b/web/src/services/api/video-provider-seedance.ts
@@ -10,6 +10,7 @@ import type { ReferenceAudio, ReferenceVideo } from "@/types/media";
 import { isPublicMediaUrl } from "./video-validation";
 import type { ApiEnvelope, RequestOptions, ResolvedAiConfig, SeedanceTask, VideoGenerationTask, VideoGenerationTaskState } from "./video-contracts";
 import type { VideoProviderDeps } from "./video-provider-deps";
+import { hasExplicitVideoFrames, resolveVideoImageReferences } from "./video-reference-roles";
 
 export function isSeedanceConfig(config: ResolvedAiConfig) {
     return config.interfaceType === "volcengine-ark-video" || isSeedanceVideoConfig(config);
@@ -20,8 +21,8 @@ export async function createSeedanceTask(deps: VideoProviderDeps, config: Resolv
     assertSeedanceAudioReferences(audioReferences);
     const isVolcengineArk = config.interfaceType === "volcengine-ark-video";
     const payload = isVolcengineArk || isArkPlanBaseUrl(config.baseUrl)
-        ? await buildSeedanceAgentPlanPayload(config, model, prompt, references, videoReferences, audioReferences, deps)
-        : await buildSeedanceVideosPayload(config, model, prompt, references, videoReferences, audioReferences, deps);
+        ? await buildSeedanceAgentPlanPayload(config, model, prompt, references, videoReferences, audioReferences, deps, options)
+        : await buildSeedanceVideosPayload(config, model, prompt, references, videoReferences, audioReferences, deps, options);
 
     try {
         const raw = await deps.transport.post<ApiEnvelope<SeedanceTask>>(seedanceApiUrl(config), payload, options);
@@ -80,13 +81,13 @@ function seedanceApiUrl(config: ResolvedAiConfig, taskId?: string) {
     return buildApiUrl(config.baseUrl, `/videos${taskId ? `/${encodeURIComponent(taskId)}` : ""}`);
 }
 
-async function buildSeedanceAgentPlanPayload(config: ResolvedAiConfig, model: string, prompt: string, references: ReferenceImage[], videoReferences: ReferenceVideo[], audioReferences: ReferenceAudio[], deps: VideoProviderDeps) {
+async function buildSeedanceAgentPlanPayload(config: ResolvedAiConfig, model: string, prompt: string, references: ReferenceImage[], videoReferences: ReferenceVideo[], audioReferences: ReferenceAudio[], deps: VideoProviderDeps, options?: RequestOptions) {
     if (audioReferences.length && !references.length && !videoReferences.length) {
         throw new Error(config.interfaceType === "volcengine-ark-video" ? "火山方舟全模态参考不支持纯音频或文本+音频，请同时添加参考图片或参考视频" : "Seedance 参考音频不能单独使用，请同时添加参考图或参考视频");
     }
     const content = config.interfaceType === "volcengine-ark-video"
-        ? await buildVolcengineArkContent(prompt, references, videoReferences, audioReferences)
-        : await buildSeedanceContent(config, prompt, references, videoReferences, audioReferences, deps);
+        ? await buildVolcengineArkContent(prompt, references, videoReferences, audioReferences, options)
+        : await buildSeedanceContent(config, prompt, references, videoReferences, audioReferences, deps, options);
     if (!content.length) throw new Error("请输入视频提示词，或连接参考图片/视频/音频");
     const profile = modelCapabilityConfigFor(config, model).video!;
     return {
@@ -100,11 +101,12 @@ async function buildSeedanceAgentPlanPayload(config: ResolvedAiConfig, model: st
     };
 }
 
-async function buildVolcengineArkContent(prompt: string, references: ReferenceImage[], videoReferences: ReferenceVideo[], audioReferences: ReferenceAudio[]) {
+async function buildVolcengineArkContent(prompt: string, references: ReferenceImage[], videoReferences: ReferenceVideo[], audioReferences: ReferenceAudio[], options?: RequestOptions) {
     const content: Array<Record<string, unknown>> = [];
+    const imagePlan = resolveVideoImageReferences(references.slice(0, SEEDANCE_REFERENCE_LIMITS.images), options, { videoCount: videoReferences.length, audioCount: audioReferences.length });
     if (prompt.trim()) content.push({ type: "text", text: prompt.trim() });
-    for (const image of references.slice(0, SEEDANCE_REFERENCE_LIMITS.images)) {
-        content.push({ type: "image_url", image_url: { url: await resolveVolcengineArkReferenceUrl(image.url || image.dataUrl, image.storageKey) }, role: "reference_image" });
+    for (const { image, role } of imagePlan) {
+        content.push({ type: "image_url", image_url: { url: await resolveVolcengineArkReferenceUrl(image.url || image.dataUrl, image.storageKey) }, role });
     }
     for (const video of videoReferences.slice(0, SEEDANCE_REFERENCE_LIMITS.videos)) {
         content.push({ type: "video_url", video_url: { url: await resolveVolcengineArkReferenceUrl(video.url, video.storageKey) }, role: "reference_video" });
@@ -121,35 +123,45 @@ async function resolveVolcengineArkReferenceUrl(value: string | undefined, stora
     throw new Error("火山方舟视频参考素材需要公网 URL 或 asset:// 素材 ID；请先将本地素材保存到对象存储");
 }
 
-async function buildSeedanceVideosPayload(config: AiConfig, model: string, prompt: string, references: ReferenceImage[], videoReferences: ReferenceVideo[], audioReferences: ReferenceAudio[], deps: VideoProviderDeps) {
+async function buildSeedanceVideosPayload(config: AiConfig, model: string, prompt: string, references: ReferenceImage[], videoReferences: ReferenceVideo[], audioReferences: ReferenceAudio[], deps: VideoProviderDeps, options?: RequestOptions) {
     if ((videoReferences.length || audioReferences.length) && !references.length) {
         throw new Error("Seedance 参考视频或参考音频需要同时连接至少 1 张主参考图");
     }
     const imageUrls = await Promise.all(references.slice(0, SEEDANCE_REFERENCE_LIMITS.images).map(resolveSeedanceVideosImageUrl));
+    const imagePlan = resolveVideoImageReferences(references.slice(0, SEEDANCE_REFERENCE_LIMITS.images), options, { videoCount: videoReferences.length, audioCount: audioReferences.length });
     const videoUrls = await Promise.all(videoReferences.slice(0, SEEDANCE_REFERENCE_LIMITS.videos).map((media) => resolveSeedanceVideosMediaUrl(media, deps)));
     const audioUrls = await Promise.all(audioReferences.slice(0, SEEDANCE_REFERENCE_LIMITS.audios).map((media) => resolveSeedanceVideosMediaUrl(media, deps)));
     const ratio = normalizeSeedanceRatio(config.size);
     const duration = normalizeSeedanceDuration(config.videoSeconds);
     const profile = modelCapabilityConfigFor(config, model).video!;
+    const imagePayload: Record<string, unknown> = {};
+    if (options?.videoEditOperation === "reference_to_video") {
+        if (imageUrls.length) imagePayload.reference_image_urls = imageUrls;
+    } else if (hasExplicitVideoFrames(options)) {
+        imagePayload.image_urls = orderedImageUrls(imageUrls, imagePlan.map(({ role }) => role));
+    } else if (imageUrls.length) {
+        imagePayload.image_url = imageUrls[0];
+        if (imageUrls.length > 1) imagePayload.reference_image_urls = imageUrls.slice(1);
+    }
     return {
         model: modelOptionName(model),
         prompt: prompt.trim(),
         aspect_ratio: ratio === "adaptive" ? "16:9" : ratio,
         duration,
         ...(profile.generateAudio.supported ? { generate_audio: boolConfig(config.videoGenerateAudio, profile.generateAudio.default) } : {}),
-        ...(imageUrls[0] ? { image_url: imageUrls[0] } : {}),
-        ...(imageUrls.length > 1 ? { reference_image_urls: imageUrls.slice(1) } : {}),
+        ...imagePayload,
         ...(videoUrls.length ? { reference_videos: videoUrls } : {}),
         ...(audioUrls.length ? { reference_audios: audioUrls } : {}),
     };
 }
 
-async function buildSeedanceContent(config: AiConfig, prompt: string, references: ReferenceImage[], videoReferences: ReferenceVideo[], audioReferences: ReferenceAudio[], deps: VideoProviderDeps) {
+async function buildSeedanceContent(config: AiConfig, prompt: string, references: ReferenceImage[], videoReferences: ReferenceVideo[], audioReferences: ReferenceAudio[], deps: VideoProviderDeps, options?: RequestOptions) {
     const content: Array<Record<string, unknown>> = [];
+    const imagePlan = resolveVideoImageReferences(references.slice(0, SEEDANCE_REFERENCE_LIMITS.images), options, { videoCount: videoReferences.length, audioCount: audioReferences.length });
     const text = buildSeedancePromptText(prompt, references, videoReferences, audioReferences);
     if (text) content.push({ type: "text", text });
-    for (const image of references.slice(0, SEEDANCE_REFERENCE_LIMITS.images)) {
-        content.push({ type: "image_url", image_url: { url: await resolveSeedanceImageUrl(image) }, role: "reference_image" });
+    for (const { image, role } of imagePlan) {
+        content.push({ type: "image_url", image_url: { url: await resolveSeedanceImageUrl(image) }, role });
     }
     for (const video of videoReferences.slice(0, SEEDANCE_REFERENCE_LIMITS.videos)) {
         content.push({ type: "video_url", video_url: { url: await resolveSeedanceMediaUrl(video, deps, "参考视频") }, role: "reference_video" });
@@ -160,6 +172,10 @@ async function buildSeedanceContent(config: AiConfig, prompt: string, references
     return content;
 }
 
+function orderedImageUrls(imageUrls: string[], roles: Array<"first_frame" | "last_frame" | "reference_image">) {
+    return ["first_frame", "last_frame", "reference_image"].flatMap((role) => imageUrls.filter((_, index) => roles[index] === role));
+}
+
 async function resolveSeedanceImageUrl(image: ReferenceImage) {
     const directUrl = image.url || image.dataUrl;
     if (isPublicMediaUrl(directUrl) || directUrl.startsWith("asset://")) return directUrl;
diff --git a/web/src/services/api/video-reference-roles.ts b/web/src/services/api/video-reference-roles.ts
new file mode 100644
index 000000000..2284107c8
--- /dev/null
+++ b/web/src/services/api/video-reference-roles.ts
@@ -0,0 +1,45 @@
+import type { ReferenceImage } from "@/types/image";
+
+import type { RequestOptions } from "./video-contracts";
+
+export type VideoImageRole = "first_frame" | "last_frame" | "reference_image";
+
+export type ResolvedVideoImageReference = {
+    image: ReferenceImage;
+    role: VideoImageRole;
+};
+
+type VideoReferenceContext = {
+    videoCount?: number;
+    audioCount?: number;
+};
+
+export function resolveVideoImageReferences(images: ReferenceImage[], options?: RequestOptions, context: VideoReferenceContext = {}): ResolvedVideoImageReference[] {
+    const operation = options?.videoEditOperation?.trim();
+    if (operation === "reference_to_video") {
+        return images.map((image) => ({ image, role: "reference_image" }));
+    }
+
+    const startFrameId = options?.videoStartFrameNodeId?.trim();
+    const endFrameId = options?.videoEndFrameNodeId?.trim();
+    if (startFrameId || endFrameId) {
+        return images.map((image) => ({
+            image,
+            role: image.id === startFrameId ? "first_frame" : image.id === endFrameId ? "last_frame" : "reference_image",
+        }));
+    }
+
+    if (context.videoCount || context.audioCount) {
+        return images.map((image) => ({ image, role: "reference_image" }));
+    }
+
+    // 传统创作页没有帧节点 ID：保留单图首帧、双图首尾帧的历史语义。
+    return images.map((image, index) => ({
+        image,
+        role: index === 0 ? "first_frame" : index === 1 && images.length === 2 ? "last_frame" : "reference_image",
+    }));
+}
+
+export function hasExplicitVideoFrames(options?: RequestOptions) {
+    return options?.videoEditOperation !== "reference_to_video" && Boolean(options?.videoStartFrameNodeId || options?.videoEndFrameNodeId);
+}
diff --git a/web/test/agnes-video.test.ts b/web/test/agnes-video.test.ts
index 01cb73896..16a531a10 100644
--- a/web/test/agnes-video.test.ts
+++ b/web/test/agnes-video.test.ts
@@ -124,6 +124,27 @@ describe("Agnes Video 2.5 request contract", () => {
         });
     });
 
+    test("treats a single storyboard character image as a reference asset", async () => {
+        const config = resolveModelRequestConfig(configForAgnes(), "agnes::agnes-video-2.5");
+        const { calls, deps } = providerDeps(config);
+        await createAgnesVideoTask(
+            deps,
+            config,
+            "agnes::agnes-video-2.5",
+            "保持角色一致",
+            [{ id: "character-1", name: "character.png", type: "image/png", dataUrl: "", url: "https://cdn.example.com/character.png" }],
+            [],
+            [],
+            { videoEditOperation: "reference_to_video" },
+        );
+
+        expect(calls[0]?.body).toMatchObject({
+            mode: "reference",
+            images: ["https://cdn.example.com/character.png"],
+        });
+        expect(calls[0]?.body as Record<string, unknown>).not.toHaveProperty("first_frame");
+    });
+
     test("polls the Agnes host root and reads metadata.url", async () => {
         const config = resolveModelRequestConfig(configForAgnes(), "agnes::agnes-video-2.5");
         const { calls, deps } = providerDeps(config, { polled: { video_id: "video-1", status: "completed", metadata: { url: "https://cdn.example.com/result.mp4" } } });
diff --git a/web/test/video-api-contracts.test.ts b/web/test/video-api-contracts.test.ts
index d85469f0e..f97b03436 100644
--- a/web/test/video-api-contracts.test.ts
+++ b/web/test/video-api-contracts.test.ts
@@ -100,6 +100,63 @@ describe("Volcengine Ark full-modal references", () => {
         const deps = { transport: {}, response: videoResponseTools } as unknown as VideoProviderDeps;
         await expect(createSeedanceTask(deps, config as never, model, "跟随节奏", [], [], [{ id: "audio-1", name: "audio.mp3", type: "audio/mpeg", url: "https://cdn.example.com/audio.mp3" }])).rejects.toThrow("不支持纯音频或文本+音频");
     });
+
+    test("显式首帧与项目角色参考图使用不同角色", async () => {
+        let requestBody: unknown;
+        const deps = {
+            transport: { post: async (_url: string, body: unknown) => (requestBody = body, { id: "task-1" }) },
+            response: videoResponseTools,
+        } as unknown as VideoProviderDeps;
+        const images = [
+            { id: "character", name: "character.png", type: "image/png", dataUrl: "", url: "https://cdn.example.com/character.png" },
+            { id: "start", name: "start.png", type: "image/png", dataUrl: "", url: "https://cdn.example.com/start.png" },
+        ];
+
+        await createSeedanceTask(deps, config as never, model, "开始运动", images, [], [], {
+            videoEditOperation: "image_to_video",
+            videoStartFrameNodeId: "start",
+        });
+
+        expect((requestBody as { content: unknown[] }).content).toContainEqual({
+            type: "image_url",
+            image_url: { url: "https://cdn.example.com/start.png" },
+            role: "first_frame",
+        });
+        expect((requestBody as { content: unknown[] }).content).toContainEqual({
+            type: "image_url",
+            image_url: { url: "https://cdn.example.com/character.png" },
+            role: "reference_image",
+        });
+    });
+});
+
+describe("Seedance /videos image roles", () => {
+    test("reference_to_video does not promote the first character image to image_url", async () => {
+        let requestBody: Record<string, unknown> = {};
+        const deps = {
+            transport: { post: async (_url: string, body: unknown) => (requestBody = body as Record<string, unknown>, { id: "task-1" }) },
+            response: videoResponseTools,
+        } as unknown as VideoProviderDeps;
+        const config = { ...defaultConfig, baseUrl: "https://video.example.com/v1", model: "seedance-2.0", videoModel: "seedance-2.0" };
+
+        await createSeedanceTask(
+            deps,
+            config as never,
+            "seedance-2.0",
+            "保持角色一致",
+            [
+                { id: "character-1", name: "1.png", type: "image/png", dataUrl: "", url: "https://cdn.example.com/1.png" },
+                { id: "character-2", name: "2.png", type: "image/png", dataUrl: "", url: "https://cdn.example.com/2.png" },
+            ],
+            [],
+            [],
+            { videoEditOperation: "reference_to_video" },
+        );
+
+        expect(requestBody.reference_image_urls).toEqual(["https://cdn.example.com/1.png", "https://cdn.example.com/2.png"]);
+        expect(requestBody).not.toHaveProperty("image_url");
+        expect(requestBody).not.toHaveProperty("image_urls");
+    });
 });
 
 describe("MiniMax explicit reference roles", () => {